| Live Cell FRET Analysis of the Conformational Changes of Human P-glycoprotein
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Author:
Date:
2021-02-20
[Abstract] The molecular mechanisms of P-glycoprotein (P-gp; also known as MDR1 or ABCB1) have been mainly investigated using artificial membranes such as lipid-detergent mixed micelles, artificial lipid bilayers, and membrane vesicles derived from cultured cells. Although these in vitro experiments help illustrate details about the molecular mechanisms of P-gp, they do not reflect physiological membrane environments in terms of lateral pressure, curvature, constituent lipid species, etc. The protocol presented here includes a detailed guide for analyzing the conformational change of human P-gp in living HEK293 cells by using intramolecular fluorescence resonance energy transfer (FRET), in which excitation of the donor fluorophore is transferred to the acceptor without emission of a photon when two ...
[摘要] [摘要] P-糖蛋白(P-gp;也称为MDR1或ABCB1)的分子机制已主要使用人造膜进行研究,例如脂质去污剂混合胶束,人造脂质双层和源自培养细胞的膜囊泡。尽管这些体外实验有助于阐明有关P-gp分子机制的细节,但它们在侧向压力,曲率,脂质成分等方面并未反映出生理膜环境。 此处提供的协议包括一个详细的指南,该指南用于通过使用分子内荧光共振能量转移(FRET)分析活HEK293细胞中人P-gp的构象变化,其中供体荧光团的激发被转移到受体上而不发射光子当两个荧光蛋白非常接近时。将FRET分析与膜通透性相结合,可以在活细胞中评估小分子(如核苷酸)对构象变化的贡献。
[背景] P-糖蛋白(P-gp)的是ATP驱动药转运该压出各种疏水有毒化合物到细胞外空间。P-gp由形成底物转运途径的两个跨膜结构域(TMD)和结合并水解ATP的两个核苷酸结合结构域(NBD)组成。传输至少需要两个P-gp状态。在向内(药物转运前)构型中,两个NBD分开,两个TMD向细胞内侧开放;在向外(药物转运)构象中,NBD是二聚体的,而TMD在细胞外侧略微开放(Kodan et al。,2020 )。自从发现P-gp (Juliano和Ling,1976; Chen等,1986; Ueda等,1986 ...
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| Rapid and Simplified Induction of Neural Stem/Progenitor Cells (NSCs/NPCs) and Neurons from Human Induced Pluripotent Stem Cells (hiPSCs)
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Author:
Date:
2021-02-05
[Abstract] Human induced pluripotent stem cells (iPSCs) and their progeny displaying tissue-specific characteristics have paved the way for regenerative medicine and research in various fields such as the elucidation of the pathological mechanism of diseases and the discovery of drug candidates. iPSC-derived neurons are particularly valuable as it is difficult to analyze neural cells obtained from the central nervous system in humans. For neuronal induction with iPSCs, one of the commonly used approaches is the isolation and expansion of neural rosettes, following the formation of embryonic bodies (EBs). However, this process is laborious, inefficient, and requires further purification of the cells. To overcome these limitations, we have developed an efficient neural induction method that allows for ...
[摘要] [摘要]人类诱导的多能干细胞(iPSC)及其后代具有组织特异性,为再生医学的研究铺平了道路,并在疾病的病理机制阐明和候选药物的发现等领域进行了研究。iPSC集-来源的神经元是特别有价值的,因为它是难以分析神经细胞获自人类的中枢神经系统。对于用iPSC诱导神经元,最常用的方法之一是在形成胚体(EB)之后分离和扩展神经玫瑰花结。然而,该过程费力,效率低下,并且需要进一步纯化细胞。为了克服这些限制,我们已经开发出一种高效神经诱导方法,该方法允许来自于7天内的iPSC神经干/祖细胞(NSCs / NPC的)的产生和功能的成熟神经元的。我们的方法产生一个PAX6 -阳性同质细胞群中,皮质神经干细胞/ NPC的,和t他所得的NSCs / NPC的可冷冻保存,膨胀,并分化在功能性成熟神经元。此外,我们的协议将比其他方法便宜,因为该协议在神经诱导期间需要较少的神经补充。本文还介绍了FM1 - 43成像测定法中,其是用于所述的iPSC衍生的突触前评估中有用的人类神经元。该协议为生成NSC / NPC和神经元提供了一种快速且简化的方法,使研究人员能够建立体外细胞模型来研究脑部疾病的病理学。
[背景]人类iPSC于2007年通过使用四种转录因子(Oct4,Sox2,Klf4和c-Myc)对皮肤成纤维细胞进行重编程而首次建立,并且表现出与胚胎干细胞(ESCs)相似的特征,包括其多能性和自我-更新(Takahashi等,2007; ...
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| Use of Optogenetic Amyloid-β to Monitor Protein Aggregation in Drosophila melanogaster, Danio rerio and Caenorhabditis elegans
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Author:
Date:
2020-12-05
[Abstract] Alzheimer’s Disease (AD) has long been associated with accumulation of extracellular amyloid plaques (Aβ) originating from the Amyloid Precursor Protein. Plaques have, however, been discovered in healthy individuals and not all AD brains show plaques, suggesting that extracellular Aβ aggregates may play a smaller role than anticipated. One limitation to studying Aβ peptide in vivo during disease progression is the inability to induce aggregation in a controlled manner. We developed an optogenetic method to induce Aβ aggregation and tested its biological influence in three model organisms–D. melanogaster, C. elegans and D. rerio. We generated a fluorescently labeled, optogenetic Aβ peptide that oligomerizes rapidly in vivo in the presence of blue light ...
[摘要] [摘要]Alzheimer'sdisease(AD)长期以来与淀粉样前体蛋白产生的细胞外淀粉样斑块(Aβ)的积聚有关。然而,在健康人身上发现了斑块,并不是所有的AD大脑都有斑块,这表明细胞外Aβ聚集体的作用可能比预期的要小。在疾病进展过程中研究Aβ肽的一个局限性是无法以可控的方式诱导聚集。我们开发了一种诱导Aβ聚集的光遗传学方法,并在三种模式生物中测试了其生物学效应:D.melanogaster、C.elegans和D.rerio。我们产生了一个荧光标记的,光生的
一种β肽,在所有生物体内,在蓝光存在下迅速寡聚。在这里,我们详细介绍了在动物模型中表达该融合蛋白的程序,使用延时光片显微镜研究对神经系统的影响,并进行代谢分析来测量由于细胞内Aβ聚集而引起的变化。这种方法利用光遗传学来研究AD的病理学,实现了目前任何其他方法都无法实现的体内时空控制。
[背景]阿尔茨海默病(AD)是一种衰弱的、与年龄相关的神经退行性疾病(Zhang等人,2011年;De ...
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